Can arrays be reused in php?

In PHP, array is a very commonly used data type used to store multiple values. Sometimes, in programming, we may need to reuse these arrays. But will reusing arrays affect the correctness of the program? This article will answer this question for you.

First, let’s take a look at what an array is. In PHP, an array is an ordered collection of key/value pairs. Array elements can be accessed using numeric or string keys. For example, the following is an array using numeric keys:

$numbers = array(1, 2, 3, 4, 5);

You can use numeric keys to access array elements, like this:

echo $numbers[0]; // 输出 1
echo $numbers[1]; // 输出 2
echo $numbers[2]; // 输出 3

The following is an array using string keys:

$fruits = array(
    "apple" => "苹果",
    "banana" => "香蕉",
    "orange" => "橙子"
);

You can access array elements using string keys, like this:

echo $fruits["apple"]; // 输出 苹果
echo $fruits["banana"]; // 输出 香蕉
echo $fruits["orange"]; // 输出 橙子

Now, it’s time to answer our original question. Yes, arrays can be reused. Specify a new variable name to create a new array using the values ​​of the original array. For example:

$numbers1 = array(1, 2, 3, 4, 5);
$numbers2 = $numbers1;

In the above code, we have created an array named $numbers1 and stored some values ​​in it and then assigned the array to another array named Array of $numbers2. This means $numbers2 now has the same values ​​as $numbers1, but it's a new, separate array.

This means that if you update the value in $numbers1, it will not affect the value in $numbers2 and vice versa. For example:

$numbers1 = array(1, 2, 3, 4, 5);
$numbers2 = $numbers1;

$numbers1[0] = 10;

echo $numbers1[0]; // 输出 10
echo $numbers2[0]; // 输出 1，因为 $numbers2 是一个新的、独立的数组

By assigning $numbers1 to $numbers2, we create a new array with the same values ​​as $numbers1 same. Therefore, changing the value in $numbers1 will not affect the value in $numbers2.

This also works for associative arrays, for example:

$fruits1 = array(
    "apple" => "苹果",
    "banana" => "香蕉",
    "orange" => "橙子"
);

$fruits2 = $fruits1;

$fruits1["apple"] = "红苹果";

echo $fruits1["apple"]; // 输出 红苹果
echo $fruits2["apple"]; // 输出 苹果，因为 $fruits2 是一个新的、独立的数组

In the above code, we create an associative array of $fruits1 and store some values ​​in in. We then assign this array to a variable called $fruits2. Therefore, $fruits2 is a new, independent array with the same values ​​as $fruits1. When we change the value in $fruits1["apple"], $fruits2["apple"] is not affected.

In short, in PHP, arrays can be reused because assigning an array to another variable creates a new, independent array. This way, when you update one array variable, you don't have to worry about it affecting other variables created by it.

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